A very rich heiress, she was married at 15 years of age to her 22-year-old first cousin, George of Hannover, the future King of Great Britain. He married Sophia Dorothea in order to secure for himself her fortunes after declining the hand of the future Queen Anne of England.
Though two children were born, George I embarked on numerous affairs. After a few years of this, Sophia Dorothea---lively, neglected and young---fell for the charms of Count von Koenigsmarck. In the beginning of their affaire, Count von Koenigsmarck also entertained
Countess von Platen, one of the mistresses of Sophia Dorothea's husband.
 Koenigsmarck's affair with Sophia Dorothea lasted some three years when they decided to elope. However, on the night of 2 July 1694, the Count disappeared. No one appeared to know what had happened to him until, in 1943, the castle of Herrenhausen was bombed and, in the ruins, the skeleton of a murdered man was found immured in the castle walls.
During the confusion that followed his disappearance, his sister, Aurora von Koenigsmarck, approached King Augustus II of Poland and asked for his assistance in the search for her brother. This approach resulted in the birth (1696) of Maurice de Saxe, who became a famous French Marshall. Sophia Dorothea, admitting to having planned to elope with the Count but not to adultery, was divorced and locked up in the castle of Ahlden for the remaining 32 years of her life.
 

Source: Leo van de Pas